Oxidative dehydrogenation in the presence of chlorine



United States Patent 3,308,198 OXIDATIVE DEHYDROGENATION IN THE PRESENCEOF CHLORINE Laimonis Bajars, Princeton, N.J., assignor to Petra-TexChemical Corporation, Houston, Tex., a corporation of Delaware NoDrawing. Filed Oct. 22, 1965, Ser. No. 502,583

13 Claims. (Cl. 260680) This application is a continuation-in-part of mycopending application Serial Number 249,997 filed January 8, 1963,entitled, Dehydrogenation, now abandoned, which in turn was acontinuation-in-part of my now abandoned applications Serial Number52,776 filed August 30, 1960, entitled, Improved DehydrogenationProcess, Serial Number 145,992 filed October 18, 1961, entitled,Dehydrogenation of Hydrocarbons, Serial Number 145,993 filed October 18,1961, entitled, Dehydrogenation Process, Serial Number 156,954 filedDecember 4, 1961, entitled, Process for Dehydrogenation, Serial Number157,000 filed December 4, 1961, entitled, Method of Dehydrogenation,Serial Number 207,105 filed July 2, 1962, and Serial Number 36,718 filedJune 17, 1960, entitled, Dehydrogenation Process.

This invention relates to a process for dehydrogenating organiccompounds and relates more particularly to the dehydrogenation oforganic compounds in the vapor phase at elevated temperatures in thepresence of oxygen, chlorine and an improved inorganic contact mass.

It has been found recently that a great variety of dehydrogenatableorganic compounds may be dehydrogenated by reacting a mixture of anorganic compound containing at least one pair of adjacent carbon atoms,each of which possess at least one hydrogen atom, chlorine or achlorinediberating material, and oxygen under or CEC grouping.

I have found, quite unexpectedly, that this process may be improved sothat increased selectivities and yields of unsaturated organic compoundderivatives containing the or CEC- grouping are obtained moreefficiently even with less chlorine and under less stringent processconditions, when such reaction is conducted in the presence of a contactmass comprising as a first component at least one element of a metal ofGroups Ia and Ila (i.e. the alkali and alkaline earth metals) togetherwith a second component which is a member selected from the groupconsisting of metals and compounds thereof of Periodic Table 1 GroupVIIIb.

The process of this invention can be applied to a great variety oforganic compounds to obtain the corresponding unsaturated derivativethereof. Such compounds normally will contain from 2 to 20 carbon atoms,at least one point below about 350 C. Such compounds may contain inaddition to carbon and hydrogen, oxygen, halo- Periodic Table, e.g., isfound in Smiths Introductory golleglegsghemistry, 3rd edition(Appleton-CenturyCrofts,

3,308,198 Patented Mar. 7, 1957 ICC gens, nitrogen and sulphur. Amongthe classes of organic compounds which are dehydrogenated by means ofthe novel process of this invention are alkanes, alkenes, alkyl halides,ethers, esters, aldehydes, ketones, organic acids, alkyl aromaticcompounds, alkyl heterocyclic compounds, cyanoalkanes, cycloalkanes andthe like. Illustrative dehydrogenation include ethylbenzene to styrene,isopropylbenzene to a-methyl styrene, ethy-lcyclohexane to styrene,cyclohexane to benzene, ethane to ethylene and acetylene, ethylene toacetylene, propane to propylene, isobutane to isobutylene, n-butane tobutene and butadiene-1,3, butene-1 to butadiene-1,3 and vinyl acetylene,cis or trans butene-2 to butadiene-1,3, butane or butene to vinylacetylene, butadiene-1,3 to vinyl acetylene, methyl butene to isoprene,isobutane to isobutylene, propionaldehyde to acrolein, ethyl chloride tovinyl chloride, propionitrile to acrylonitrile, methyl isobutyrate tomethyl methacrylate, and the like. Other representative materials whichare readily dehydrogenated in the novel process of this inventioninclude ethyl toluene, the alkyl chlorobenzenes, ethyl naphthalene,isobutyronitrile, propyl chloride, isobutyl chloride, ethyl fluoride,ethyl dichloride, butyl chloride, the chlorofluoroethanes, methylethylketone, diethyl ketone, methyl propionate, and the like. This inventionis useful in the preparation of vinylidene compounds containing at leastone CH =C group, that is, a compound possessing at least one groupcontaining a terminal methylene group attached by a double bond to acarbon atom, and 2 to 12 carbon atoms and is particularly useful in thedehydrogenation of hydrocarbons containing 2 to 5 carbon atoms oraliphatic nitriles of 3 to 4 carbon atoms. Preferred compounds to bedehydrogenated are hydrocarbons of 4 to 8 carbon atoms having at leastfour contiguous non-quaternary carbon atoms. Aliphatic acyclichydrocarbons of from 4 to 5 or 6 carbon atoms are preferred. Theinvention is further particularly adapted to provide butadiene-1,3 frombutane and butene and isoprene from isopentane and isopentene in highyields and excellent conversion and selectivity.

As shown by the examples below and the disclosures herein, the novelprocess of this invention is applicable to a great variety of organiccompounds containing 2 to 20 carbon atoms and at least one pair ofadjacent carcluding both alicyclic compounds and aromatic compounds ofthe formula wherein Ar is phenyl or naphthyl, R is hydrogen or methyland X and Y are hydrogen or alkyl radicals containing 1 to 4 carbonatoms, or halogen; alkyl ketones containing 4 to 6 carbon atoms;aliphatic aldehydes containing 3 to 6 carbon atoms; cyanoalkanescontaining 2 to 6 carbon atoms; halo-alkanes and halo-alkenes containing2 to 6 carbon atoms, particularly chloroand fluoro-alkanes and the like.Vinylidene compounds containing the CH =C group, that is, containing aterminal methylene group attached by a double bond to a carbon atom, arereadily obtained from organic compounds containing 2 to 12 carbon atomsand at least one group wherein adjacent carbon atoms are singly bondedand possess at least one hydrogen each. For example, vinylidene halides;vinyl esters; acrylic acid and alky-land halo-acrylic acids and esters;vinyl aromatic compounds; vinyl ketones; vinyl heterocyclic compounds;diolefins containing 4 to 6 carbon atoms, olefins containing 2 to 8carbon atoms, and the like are obtained as products. The vinylidenecompounds normally contain from 2 to 12 carbon atoms and are well knownas a commercially useful class of materials for making valuable polymersand copolymers therefrom.

Useful feeds as starting materials may be mixed hydrocarbon streams suchas refinery streams. For example, the feed material may be theolefin-containing hydrocarbon mixture obtained as the product from thedehydrogenation of hydrocarbons. Another source of feed for the presentprocess is from refinery by-products. Although various mixtures ofhydrocarbons are useful, the preferred hydrocarbon feed contains atleast 50 weight percent butene-1, butene-2, n-butane and/ orbutadiene-1,3 and mixtures thereof, and more preferably contains atleast 70 percent n-butane, butene-1, butene-2 and/or butadiene-l,3 andmixtures thereof. Any remainder usually will be aliphatic hydrocarbons.The process of this invention is particularly effective indehydrogenating acyclic aliphatic'hydrocarbons to provide a hydrocarbonproduct wherein the major unsaturated product has the same number ofcarbon atoms as the feed hydrocarbon.

The chlorine-liberating material may be such as chlorine itself,hydrogen chloride, aliphatic chlorides of 1 to 6 carbon atoms such asmethyl chloride or ethylene dichloride, carbon tetrachloride, ammoniumchloride and the like. Preferably the chlorine-containing material willeither volatilize or decompose at a temperature of no greater than 100C. to liberate the required amount of chlorine or hydrogen chloride.Usually an amount of at least .005 or 0.01 mol of chlorine per mol oforganic compound to be dehydrogenated will be used. It is one of theunexpected advantages of this invention that only very small amounts ofchlorine are required. Less than 0.5 mol of chlorine, as 0.2 mol, permol of organic compound to be dehydrogenated may be employed. Suitableranges are such as from about .005 or 0.01 to 0.05, 0.1, 0.25 or 0.3 molof chlorine per mol of the compound to be dehydrogenated. Excellentresults are obtained when the chlorine is present in an amount of lessthan 0.3 mol of chlorine per mol of the compound to be dehydrogenated.It is understood that when a quantity of chlorine is referred to herein,both in the specification and the claims, that this refers to thecalculated quantity of chlorine in all forms present in the vapor spaceunder the conditions of reaction regardless of the initial source or theform in which the chlorine is present. For example, a reference to 0.05mol of chlorine would refer to the quantity of chlorine present whetherthe chlorine was fed as 0.05 mol of C1 or 0.10 mol of HCl. Preferablythe chlorine will be present in an amount no greater than or mol percentof the total gaseous mixture in the dehydrogenation zone.

The minimum amount of oxygen employed will generally be at least aboutone-fourth mol of oxygen per mol of organic compound to bedehydrogenated. Large amounts as about 3 mols of oxygen per mol oforganic compound may be used. Excellent yields of the desiredunsaturated derivatives have been obtained with amounts of oxygen fromabout 0.4 to about 1.2 or 1.5 mols of oxygen per mol of organic compoundand suitably may be within the range of about 0.4 to 2 mols of oxygenper mol of organic compound. Preferably the oxygen will be present in anamount of at least 0.4 or 0.6 mol per mol of compound to bedehydrogenated. Oxygen may be supplied to the reaction system as pureoxygen or as oxygen diluted with inert gases such as helium, carbondioxide, as air and the like. In relation to chlorine, the amount ofoxygen employed should be at least 2 mols of oxygen per mol of chlorineand preferably will be at least or greater than 2.50 mols of oxygen permol of chlorine. A suitable ratio is at least 3.0 mols of oxygen per molof chlorine.

While the total pressure on systems employing the process of thisinvention normally will be at or in excess of atmospheric pressure,vacuum may be used. Higher pressures, such as about or 200 p.s.i.g. maybe used. The partial pressure of the organic compound under reactionconditions usually will be equivalent to 'below 10 inches mercuryabsolute when the total pressure is atmospheric. Better results andhigher yields of desired product are normally obtained when the partialpressure of the organic compound is equivalent to less than aboutone-third or one-fifth of the total pressure. Also because the initialpartial pressure of the hydrocarbon to be dehydrogenated is generallyequivalent to less than about 10 inches of mercury at a total pressureof one atmosphere, the combined partial pressure of the hydrocarbon tobe dehydrogenated plus the dehydrogenated hydrocarbon will also beequivalent to less than about 10 inches of mercury. For example, underthese conditions, if butene is being dehydrogenated to butadiene, at notime will the combined partial pressure of the butene and butadiene begreater than equivalent to about 10 inches of mercury at a totalpressure of one atmosphere. Preferably the hydrocarbon to bedehydrogenated should be maintained at a partial pressure equivalent toless than one-third the total pressure, such as no greater than sixinches or no greater than four inches of mercury, at a total pressure ofone atmosphere. The desired pressure is obtained and maintained bytechniques including vacuum operations, or by using helium, organiccompounds, nitrogen, steam and the like, or by a combination of thesemethods. Steam is particularly advantageous and it is surprising thatthe desired reactions to produce high yields of product are effected inthe presence of large amounts of steam. Steam is particularlyadvantageous to obtain the required low partial pressure on the organiccompound in the process. When steam is employed, the ratio of steam toorganic compound is normally above about two mols of steam per mol oforganic compound such as within the range of about 2 or 5 to 20 or 30mols, although larger amounts of steam as high as 40 mols have beenemployed. The degree of dilution of the reactants with steam and thelike is related to maintaining the partial pressure of the organiccompound in the system at below about one-third atmos phere andpreferably below 10 inches mercury absolute When the total pressure onthe system is one atmosphere. For example, in a mixture of one mol ofbutene, three mols of steam and one mol of oxygen under a total pressureof one atmosphere the butene would have an absolute pressure ofone-fifth of the total pressure, or roughly six inches of mercuryabsolute pressure. Equivalent to this six inches of mercury buteneabsolute pressure at atmos pheric pressure would be butene mixed withoxygen and chlorine under a vacuum such that the partial pressure of thebutene is six inches of mercury absolute. A combination of a diluentsuch as steam together with a vacuum may be utilized to achieve thedesired partial pressure of the hydrocarbon. For the purpose of thisinvention, also equivalent to the six inches of mercury butene absolutepressure at atmospheric pressure would be the same mixture of one mol ofbutene, three mols of steam and one mol of oxygen under a total pressuregreater than atmospheric, for example, a total pressure of 15 or 20inches mercury above atmospheric. Thus, when the total pressure on thereaction zone is greater than one atmosphere, the absolute values forthe pressure of butene will be increased in direct proportion to theincrease in total pressure above one atmosphere. Another feature of thisinvention is that the combined partial pressure of the hy-' drocarbon tobe dehydrogenated plus the chlorine-liberating material will preferablyalso be equivalent to less than 10 inches of mercury, and preferablyless than 6 or 4 inches of mercury, at a total pressure of oneatmosphere.

The lower limit of organic compound partial pressure will be dictated bycommercial considerations and normally Will be greater than about 0.1inch of mercury absolute.

The temperature of the reaction is from above 400 C. to about 800 C. or1000 C. Preferably the temperatures will be from at least 450 C. to 900C., and generally will be at least about 500 C. The optimum temperaturemay be determined as by thermocouple at the maximum temperature of thereaction. Usually the temperature of reaction will be controlled betweenabout 450 C. and about 750 C. or 800 C.

The flow rates of the gaseous reactants may be varied quite widely andgood results have been obtained with organic compound gaseous flow ratesranging from about 0.25 to about 3 liquid volumes of organic compoundper volume of reactor packing per hour, the residence or contact time ofthe reactions in the reaction zone under any given set of reactionconditions depending upon the factors involved in the reaction.Generally, the flow rates will be within the range of about 0.10 to 25or higher liquid volumes of the hydrocarbon to be dehydrogenated,calculated at standard conditions of 0 C. and 760 mm. of mercury pervolume of reactor space containing catalyst per hour (referred to aseither LHSV or liquid v./v./hr.). Usually the LHSV will be between 0.15and 15. The volume of reactor containing catalyst is that volume ofreactor space including the volume displaced by the catalyst. Forexample, if a reactor has a particular volume of cubic feet of voidspace, when that void space is filled with catalyst particles theoriginal void space is the volume of reactor containing catalyst for thepurpose of calculating the flow rates. The residence or contact time ofthe reactants in the reaction zone under any given set of reactionconditions depends upon all the factors involved in the reaction.Contact times ranging from about 0.01 to about two seconds at about 450C. to 750 C. have been used. A wider range of residence times may beemployed, as 0.001 second to about or seconds. Residence time is thecalculated dwell time of the reaction mixture in the reaction zoneassuming the mols of product mixture are equivalent to the mols of feedmixture.

For conducting the reaction, a variety of reactor types may be employed.Fixed bed reactors may be used and fluid and moving bed systems areadvantageously applied to the process of this invention. In any of thereactors suitable means for heat removal may be provided. Tubularreactors of large diameter which are loaded or packed with the solidcontact mass are satisfactory.

Good results have been obtained when the exposed surface of the solidcontact mass is greater than about 25 square feet, preferably greaterthan about 50 square feet per cubic foot of reactor as 75 or 100 orhigher. Of course, the amount of catalyst surface may be much greaterwhen irregular surface catalysts are used. When the catalyst is in theform of particles, either supported or unsupported, the amount ofcatalyst surface may be expressed in terms of the surface area per unitweight of any particular volume of catalyst particles. The ratio ofcatalytic surface to weight will be dependent upon various factorsincluding the particle size, particle distribution, apparent bulkdensity of the carrier, and so forth. Typical values for the surface toweight ratio are such as about /2 to 200 square meters per gram,although higher and lower values may be used.

Excellent results have been obtained by packing the reactor withcatalyst particles as the method of introducing the catalytic surface.The size of the catalyst particles may vary widely but generally themaximum particles size will at least pass through a Tyler StandardScreen which has an opening of 2 inches, and generally the largestparticles of catalyst will pass through a Tyler Screen with As measuredby the Innes nitrogen absorption method on a representative unit volumeof catalyst particles. The Innes is reported in Innes, W. B., Anal.Chem, 23, 759

one inch openings. Thus, the particle size when particles are usedpreferably will be from about 10 microns to a particle size which willpass through a Tyler Screen with openings of 2 inches. If a carrier isused the catalyst may be deposited on the carrier by methods known inthe art such as by preparing an aqueous solution or dispersion of thecatalyst, mixing the carrier with the solution or dispersion until theactive ingredients are coated on the carrier. The coated particles maythen be dried, for example, in an oven at about 110 C. Various othermethods of catalyst preparation known to those skilled in the art may beused. Very useful carriers are the Alundums, silicon carbide, theCarborundums, pumice, kieselguhr, asbestos, and the like. When carriersare used, the amount of catalyst composition on the carrier willgenerally be in the range of about 2 to weight percent of the totalweight of the active catalytic material plus carrier. Another method forintroducing the required surface is to utilize as a reactor a smalldiameter tube wherein the tube wall is catalytic or is coated withcatalytic material. If the tube wall is the only source of catalystgenerally the tube will be of an internal diameter of no greater thanone inch such as less than inch in diameter or preferably will be nogreater than about /2 inch in diameter. The technique of utilizing fluidbeds lends itself well to the process of this invention.

In the above descriptions of catalyst compositions, the compositiondescribed is that of the surface which is exposed in the dehydrogenationzone to the reactants. That is, if a catalyst carrier is used, thecomposition described as the catalyst refers to the composition of thesurface and not to the total composition of the surface coating pluscarrier. The catalytic compositions are intimate combinations ormixtures of the ingredients. These ingredients may or may not be presentas alloys. Catalyst binding agents onfillers may be used, but these willnot ordinarily exceed about 50 percent or 65 percent by weight of thecatalytic surface. The defined catalytic components will be the mainactive constituents in the catalyst and the catalyst may consistessentially of the defined catalytic components. The weight percent ofthe defined catalytic atoms will generally be at least 20 percent, andare preferably at least 35 percent of the composition of the catalytssurface exposed to the reaction gases and will generally be at least 51or about 80 atomic weight percent of any cations in the surface, such asat least 80 atomic percent of any metal cations in the surface.

The defined catalyst combinations may be employed in any form, e.g., aspellets, tablets, as coatings on carriers or supports, and the like, inboth fixed and fluidized beds. Other methods of catalyst preparationknown to those skilled in the art may also be used.

According to this invention, the catalyst is autoregener- -ative andthus the process is continuous. Little or no energy input is requiredfor the process and it may be operated essentially adiabatically.Moreover, small amounts of tars and polymers are formed as compared toprior art processes. It is also an advantage of this invention thattriple bond containing compounds are more easily obtained than withcatalysts containing only one of the defined components.

In the examples given below the conversions, selec tivities and yieldsare expressed as mol percent based on the mols of the compound to bedehydrogenated fed to the reactor. The temperature of reaction listed isapproximately the maximum temperature in the reactor. The catalysts arepresent as fixed beds.

The Group Ia and 11a compounds used include, for example, oxides,hydroxides and salts such as the phosphates, sulfates, halides and thelike. Useful compounds include, for example, lithium chloride, lithiumoxide, lithium bromide, lithium fluoride, lithium phosphate, sodiumhydroxide, sodium oxide, sodium chloride, sodium sulfate, berylliumoxide, sodium bromide, sodium iodide, sodium phosphate, sodium fluoride,potassium chloride,

potassium bromide, potassium sulfate, potassium iodide, potassiumnitrate, potassium citrate, potassium hydroxide, potassium oxide,potassium phosphate, rubidium chloride, rubidium bromide, rubidiumiodide, rubidium oxide, magnesium acetate, magnesium bromide, magnesiumoxide, magnesium iodide, calcium oxide, calcium acetate, calciumoxalate, calcium chloride, calcium bromide, calcium iodide, calciumphosphate, calcium fluoride, strontium oxide, strontium hydroxide,strontium chloride, strontium bromide, barium oxide, barium chloride,barium hydroxide, barium sulfate, barium bromide, barium iodide,beryllium chloride, and the like, and mixtures thereof. Preferred GroupIa and 11a metal elements are lithium, sodium, magnesium, potassium,calcium, strontium and barium, such as the oxides, phosphates, iodides,bromides, chlorides or fluorides of these metals. The oxides and halidesand mixtures thereof are particularly preferred. Many of the Group Iaand Ila compounds may change during the preparation of the catalyst,during heating in a reactor prior to use in the process of thisinvention, or are converted to another form under the described reactionconditions, but such materials still function as an effective compoundin the defined process. For example, the halides may be converted to theoxides or vice versa under the conditions of reaction. The amount ofGroup Ia metal compound or Group IIa metal compound with the additionalmetal or inorganic compound thereof may be varied quite widely and whilesmall amounts, as low as one-tenth percent based on the total catalyst,have been used, much larger amounts may be employed in concentrations upto where the Group Ia or Ila metal compound is the larger constituent inthe composition, such as up to 50 weight percent -or more, as 95percent. Normally up to'50 percent, and more usually about one to abouttwenty-five percent of the Group Ia or Group IIa compound, such as aboutone to ten percent, with the remainder being the defined secondinorganic metal compound, is satisfactory. On an atomic basis, thecombined amount of the metal atoms of Group Ia and/ or 1111 will be fromat least about 0.001 atoms per atom of the defined second catalystcomponent and mixtures thereof. Excellent results are obtained at ratiosof about 0.01 to 1.0 or 1.5 atoms of Group Ia and Hal per atom of theelements from the second specified group, such as from or about 0.01 or0.02 to 0.5 atoms of Group Ia and 1111 per atom of the elements from thesecond specified group.

' A variety of metals or metal compounds of Periodic Table Group VIIIbmay be used as the second component in conjunction with the Group Ia andIla metal compounds. Metals of the described second component group inelemental form may be employed and are included within the scope of thisinvention. The metals generally are changed to inorganic compoundsthereof, at least on the surface, under the reaction conditions setforth herein. Particularly effective are inorganic compounds such as theoxides and salts including the phosphates and the halides, such as theiodides, bromides, chlorides and fluorides. Inorganic compounds whichare useful as the second component in the compounded contact mass forthe process of this invention include palladium oxide, ferric oxide,ferrous oxide, iron phosphate, iron phosphide, nickel oxide, ironcarbonate, iron sulfate, cobalt nitrate, cobaltous oxide, cobalticoxide, ferric phosphate, ferrous chloride, and the like. Preferably thecatalyst will be solid under the conditions of reaction. Excellentcatalysts are those comprising atoms of iron, cobalt, nickel andpalladium, such as the oxides, phosphates, iodides, bromides, chloridesor fluorides of these elements. Many of the salts, oxides and hydroxidesof the metals of the listed groups may change during the preparation ofthe catalyst, during heating in a reactor prior to use in the process ofthis invention, or are converted to another form under the describedreaction conditions, but such materials still function as an effectivecompound in the defined process. For example, many of the metalnitrates, nitrites, carbonates, hydroxides, acetates, and the like maybe converted to the corresponding oxide or chloride under the reactionconditions defined herein. Salts which are stable or partially stable atthe defined reaction temperatures are likewise effective under theconditions of the described reaction, as well as compounds which areconverted to another form in the reactor. At any rate, the catalysts areeffective if the defined catalyst is present in a catalytic amount incontact with the reaction gases. Useful catalyst combinations includeiron oxide and lithium chloride, iron oxide and calcium chloride,ferrous chloride and potassium chloride, ferrous chloride and rubidiumchloride, ferrous chloride and lithium hydroxr ide, iron oxide andlithium hydroxide, ferrous sulfate and potassium sulfate, ferric oxideplus lithium oxide and barium oxide, ferric oxide, lithium chloride andbarium hydroxide, cobalt chloride and calcium chloride and the like. InGroup VIIIb the preferred elements are those in the fourth period, i.e.,iron, cobalt and nickel. Iron is particularly preferred and superiorresults have been obtained with iron.

Examples 1 to 5 are run in a tubular Vycor 3 reactor, filled with thedescribed solid contact masses, equipped with an external electricfurnace. The reaction conditions and the active materials used are setforth in the specific examples. The organic compound and oxygen areadded at the top of the reactor, the halogen is added to this stream asit enters the reactor and the steam is added separately opposite thisstream. The results are reported as mol percent conversion, selectivelyand yield of the desired unsaturated product per pass.

Example 1 A contact mass is prepared by slurrying ferric oxide in watercontaining 2.5 percent lithium chloride based on the ferric oxide. Thisslurry is evaporated in the presence of 4 to 8 mesh AMC pellets andafter the pellets were dried they are placed in the Vycor reactor.Reactants are passed through. the reactor in a molar ratio of one mol ofbutene, 15 mols of steam, 0.85 mol of oxygen and 0.115 mol of chlorine(as 37 percent hydrochloric acid) at a temperature of only 500"v C.Under these reaction conditions, butadiene-l,3 is obtained from butenein a yield of 46 percent per pass at a conversion of 51 percent andselectivity of percent. When this example is repeated at 500 C. and thecontact mass contains only ferric oxide, less butadiene-1,3 is obtainedthan when the contact mass also contains lithium chloride.

Example 2 Butene is dehydrogenated over a contact mass containing 97.5percent ferric oxide and 2.5 percent calcium chloride deposited on AMCpellets as described above. Butene is dehydrogenated over this contactmass in a molar ratio of reactants of one mol of butene, 15 mols ofsteam, 0.85 mol of oxygen and 0.115 mol of chlorine (fed as hydrogenchloride) at a temperature of 600 C. Butadiene-1,3 is obtained in ayield of 69 percent per pass at a conversion of 82 percent andselectivity of 84 percent. When this example is repeated with a contactmass containing 90 percent ferric oxide and 10 percent calcium chlorideat 650 C. isoprene is obtained in good yield from isopentene.

When the examples above are repeated with other contact masses such asmixtures prepared from ferric oxide and 5 percent calcium chloride;ferrous chloride and potassium chloride; ferrous chloride and sodiumchloride; ferrous chloride and rubudi-um chloride; ferric oxide andsodium chloride; ferrous chloride, lithium chloride and calciumchloride; ferric oxide, calcium oxide and lithium chloride; iron sulfateand potassium sulfate; cobalt oxide 3 Vycor is the trade name of CorningGlass Works, Corning,

and lithium chloride; ferrous oxide and lithium chloride; ferric oxideand potassium sulfate; ferric oxide, calcium oxide and lithium chloride;cobalt chloride and calcium chloride; iron phosphate and calciumchloride; ferric oxide and rubidium chloride; ferric oxide and lithiumbromide; ferrous oxide and calcium carbonate; good yields ofbutadiene-1,3 are obtained from butene.

Examples 3 t Both iron oxide alone and iron oxide modified with LiOH areused as catalysts. The catalytic coating is coated on 6 mm. VycorRaschig rings from Water slurries thereof. A mixture of butene-2,oxygen, steam and hydrogen chloride is fed into the Vycor reactorcontaining the coated rings at a flow rate of one-half liquid v./v./hr.of butene-2 in a molar ratio of one mol of butene-2 to 0.85 mol ofoxygen, mols of water and 0.115 mol of chlorine (fed as aqueous 37percent hydrogen chloride). The temperatures of reaction are shown. Theyield of butadiene-1,3 and conversion and selectivity are set forth inthe table below.

Ex. Coating Yield, Conver- Selectivity,

Percent sion, Percent Percent 3 Ferric Oxide 650 C 31 40 77 4 FerricOxide plus 2.5%

LiOH 600 C. 50 56 90 5 650 C 51 60 85 When the above Example 3 isrepeated, but with the reactor containing Vycor Raschig rings coatedwith 100 percent lithium hydroxide, the results obtained in terms ofbutadiene-1,3 at 650 C. are no better than those obtained with ironoxide alone. An unexpected synergistic effect is obtained when a metalcompound such as iron oxide is mixed with an alkali metal hydroxide suchas lithium hydroxide, since the yields obtained with these two materialsseparately are lower than those obtained when the combination isemployed.

Example 6 Example 4 is repeated with the exceptions that the catalystcontains 90 percent by weight Fe O and 10 percent by weight LiOH and thereaction temperature is 550 C. The selectivity is 80 percent.

Example 7 Ethylbenzene is dehydrogenated to styrene in a oneinchinternal diameter Vycor reactor according to the general procedure usedabove. The flow rate of ethylbenzene is 0.5 LHSV, the mol ratio ofoxygen to ethylbenzene is 1.0 and 10 mols of steam were used per mol ofethylbenzene. Hydrogen chloride solution is added at a rate equivalentto 0.09 mol of C1 per mol of ethyl benzene. The catalyst is Fe O on acarrier. At 600 C. styrene is produced at a selectivity of 45 molpercent.

Example 8 Example 7 is repeated with the exception that the catalyst is90 percent by weight Fe O and 10 percent CaO. The selectivity isincreased to 63 percent.

Example 9 1 0 Example 10 n-Butane is dehydrogenated to a mixture ofbutadiene- 1,3 and butene. The reactor of Example 1 is utilized and thecatalyst is deposited on 6 mm. x 6 mm. Vycor Raschig rings. The catalystis 97.5 weight percent Fe O plus 2.5 percent LiOH. Chlorine is employedin an amount of 0.23 mol, oxygen as 1.5 mols and steam as 15 molsrespectively per mol of n-butane. The LHSV is /2 (0,11 ltr./min. STP).The reactor is 1" in diam eter and the catalyst bed is about 8" deep. At550 C. the selectivity to butadiene and butene is 71 percent.

Example 11 Example 10 is repeated substituting 10 mols of helium for thesteam and by using a reactor temperature of 550 C. The selectivity is 74percent and the yield is 55 percent.

Example 12 Example 10 is repeated substituting 8 mols of air for thesteam and oxygen of Example 10. At 600 C. the selectivity is 68 percentand the yield is 54 percent.

Example 13 Butene-2 is dehydrogenated at /2 l.v./v./hr. (0.11 ltr./ min.STP) and 600 C. using 15 mols of steam, .85 mol of oxygen and .115 molof C1 per mol of butene-2. The catalyst is C0 0 The selectivity is 51percent and the yield is 27 percent.

Example 14 Example 13 is repeated with the exception that the catalystis 97.5 percent by weight C0 0 and 2.5 percent LiOH. The selectivity is71 percent and the yield is increased to 43 percent.

Example 15 Propane is dehydrogenated to propylene at a selectivity of 61percent. The catalyst is 97.5 percent by weight Fe O and 2.5 percentLiOH. The ratios are .11 mol C1 15 steam and 1.0 oxygen respectively permol of propane. The temperature is 600 C. and the LHSV is 1.0.

The process of this invention is particularly applicable to thedehydrogenation of hydrocarbons, including dehydroisomerization anddehydrocyclization, to form a variety of acyclic compounds,cycloaliphatic compounds, aromatic compounds and mixtures thereof. Forexample, 2-ethylhexene-1 may be converted to a mixture of aromaticcompounds such as toluene, ethyl benzene, pxylene, o-xylene and styrene.

I claim:

1. The method for dehydrogenating organic compounds having 2 to 20carbon atoms selected from the group consisting of hydrocarbons andnitriles to produce a dehydrogenated product having the same number ofcarbon atoms and the same structure with the exception of the removedhydrogen atoms which comprises heating in the vapor phase at atemperature of about 400 C. the said organic compound having a groupwith'oxygen in a molar ratio of greater than onefourth mol of oxygen permol of said organic compound, chlorine in an amount of less than 0.3 molof chlorine per mol of said organic compound and in an amount of nogreater than 10 mol percent of the total gaseous mixture in thedehydrogenation zone, the ratio of the mols of said oxygen to the molsof said chlorine being at least 2.0, the partial pressure of saidorganic compound being equivalent to less than one-half the totalpressure in the presence of a catalyst comprising as its main activeconstituent (1) a compound selected from the group consisting of oxides,salts and hydroxides of alkali and alkaline earth metals and mixturesthereof, and (2) metals or compounds thereof of Periodic Table GroupVIIlb, the said (1) being present in an amount of up to 50 weightpercent of the total weight of the said (1) and (2) with the weightpercent of the cations of the defined (l) and 2) being at least 51percent of any cations in the catalyst surface exposed to the reactiongases.

7 2. The method of claim 1 wherein the said organic compound is ahydrocarbon having from 2 to 12 carbon atoms.

3. The method of claim 1 wherein the said organic compound is an acyclicaliphatic hydrocarbon of 4 to 6 carbon atoms.

4. The method of claim 1 wherein the said organic compound is ahydrocarbon selected from the group consisting of n-butene, n-butane,isopentene, isopentane and mixtures thereof.

5. The method of claim 4 wherein the said temperature is at least 450 C.

6. The method of claim 4 wherein steam is employed in the said vaporphase in an amount of from 2 to 30 mols of steam per mol of saidhydrocarbon.

7. The method of claim 4 wherein the oxygen is present in an amount ofgreater than 3.0 mols of oxygen per mol of said chlorine and the saidchlorine is present in an amount of from .005 to 0.25 mol of chlorineper mol of said hydrocarbon.

8. The method of claim 4 wherein the alkali and alkaline earth metalcompounds are present in an amount of from about .01 to 0.5 atom of thealkali or alkaline earth metal elements per atom of the metal elementsof the said (2).

9. A method for dehydrogenating hydrocarbons containing 4 to carbonatoms which comprises reacting in the vapor phase at a temperaturebetween 400 C. and about 750 C. an aliphatic hydrocarbon containing 4 to5 carbon atoms with oxygen in a molar ratio of about 0.4 mol to about 2mols of oxygen per mol of hydrocarbon, and above 0.001 mol to less than0.2 mol per mol of aliphatic hydrocarbon of chlorine, at a partialpressure of said hydrocarbon of less than about onethird the totalpressure in the presence of a mixture of (l) a compound selected fromthe group consisting of alkali metal oxides, alkaline metal hydroxides,alkaline earth metal oxides and alkaline earth metal hydroxides, and (2)an inorganic metal compound of a Group VIlIb metal and mixtures thereof,the said (1) being present in an amount of from about one to twenty-fiveweight percent of the total weight of the (l) and (2) with the totalweight percent of the cations of the said (1) and (2) being at least 51percent of any cations in the catalyst surface.

10. The method of claim 1 wherein the metal of said (2) comprises iron.

11. The method of claim 1 wherein the metals of the said (1) areselected from the group consisting of lithium, sodium, magnesium,potassium, calcium, strontium, barium and mixtures thereof.

12. The method of claim 1 wherein the metals of the said (1) and .(2)are present as oxides, halides, or mixtures thereof.

13. The method of claim 9 wherein the said (2) comprises iron oxide.

OTHER REFERENCES Ladoo et al., Nonmetallic Minerals published byMcGraw-Hill Book Co., New York (1951), page 408 relied on.

DELBERT E. GANTZ, Primary Examiner.

G. E. SCHMIT'KONS, Assistant Examiner.

1. THE METHOD FOR DEHDROGENATING ORGANIC COMPOUNDS HAVING 2 TO 20 CARBONATOMS SELECTED FROM THE GROUP CONSISTING OF HYDROCARBONS AND NITRILES TOPRODUCE A DEHYDROGENATED PRODUCT HAVING THE SAME NUMBER OF CARBON ATOMSAND THE SAME STRUCTURE WITH THE EXCEPTION OF THE REMOVED HYDROGEN ATOMSWHICH COMPRISES HEATING IN THE VAPOR PHASE AT A TEMPERATURE OF ABOUT400*C. THE SAID ORGANIC COMPOUND HAVING A >CH-CH< GROUP WITH OXYGEN IN AMOLAR RATIO OF GREATER THAN ONEFOURTH MOL OF OXYGEN PER MOL OF SAIDORGANIC COMPOUND, CHLORINE IN AN AMOUNT OF LESS THAN 0.3 MOL OF CHLORINEPER MOL OF SAID ORGANIC COMPOUND AND IN AN AMOUNT OF NO GREATER THAN 10MOL PERCENT OF THE TOTAL GASEOUS MIXTURE IN THE DEHYDROGENATION ZONE,THE RATIO OF THE MOLS OF SAID OXYGEN TO THE MOLS OF SAID CHLORINE BEINGAT LEAST 2.0, THE PARTIAL PRESSURE OF SAID ORGANIC COMPOUND BEINGEQUIVALENT TO LESS THAN ONE-HALF THE TOTAL PRESSURE IN THE PRESENCE OF ACATALYST COMPRISING AS ITS MAIN ACTIVE CONSTITUENT (1) A COMPOUNDSELECTED FROM THE GROUP CONSISTING OF OXIDES, SALTS AND HYDROXIDES OFALKALI AND ALKALINE EARTH METALS AND MIXTURES THEREOF, AND (2) METALS ORCOMPOUNDS THEREOF OF PERIODIC TABLE GROUP VIIIB, THE SAID (1) BEINGPRESENT IN AN AMOUNT OF UP TO 50 WEIGHT PERCENT OF THE TOTAL WEIGHT OFTHE SAID (1) AND (2) WITH THE WEIGHT PERCENT OF THE CATIONS OF THEDEFINED (1) AND (2) BEING AT LEAST 51 PERCENT OF ANY CATIONS IN THECATALYST SURFACE EXPOSED TO THE REACTION GASES.